FAST® 4 Barrel Throttle Bodies incorporate tapered and radiused throttle bores and precisely machined progressive linkage for smooth throttle operation and unparalleled airflow. More airflow equals more horsepower. Inward opening throttle blades eliminate part throttle directional influence by the blades that can cause poor air distribution. Shorter height for better airflow, easier packaging for tight hood clearance & reduced weight. Throttle blades attached to stainless steel shafts w/ aircraft quality hardware and peened to assure positive retention. Bodies are machined from 6061-T6 billet aluminum for consistent quality, excellent appearance and light weight. Brass throttle blades control vibration & reduce thermal expansion.